Abstract

I should say I get really confuzed when figuring out bootloader->kernel->init, so this might get messy.

The following is some pseudosteps which I think would create an ISO.

Create a stage4, but instead of tar compression, use squashfs.

From brief exploration, it seems targets/gentoo/stage/capture will be the place to edit.

Make an kernel w/ genkernel; should be able to handle squashfs.

If not with genkernel, get a generic kernel (monolithic or modular), make initramfs with better-initramfs.

Prepare isolinux.

ISOLINUX's documentation is a little arcane, and I have no idea how gentoo's livedvd handles EFI.

...

Profit!

LiveCD/DVD Generation

Squashfs compression in Metro

Taking a look at etc/builds/funtoo/build.conf, there is no reference to what type to capture (see targets/gentoo/stage/capture/). I have no idea where to specify ami (and therefore any other capture method).

Metro would need to create a stage4, then use that as a seed for an ISO (or, shall we do something completely different?).

Update 1

Metro comes bundled with a stage4 target. The stage4 collects targets/gentoo/stage/capture/tar.spec; some quick edits later it should be squashfs-compressed.

Init

Update 3

Autologin works (not like gentoo livecd, but it drops to a root shell which is what we want). Autodetection goes under OpenRC tweaking.

Bootable kernel

I'm pretty sure a genkernel kernel can be put on a livecd as-is, but by now the squashfs is set in stone; too late for the modules to be placed in /lib/modules.

I seem to remember a gentooor maybe it was ubuntu... livecd with grub. How?

Update 1

With "stage5", we actually have the kernel and modules inside the squashfs (so no problem there); the problem is now we need it _outside_...

Probably not a major problem. unsquashfs can selectively extract any necessaries from it.

The final part of the process is bringing it altogether. I can't imagine that metro can take a stage5.sqfs and make funtoo-${subarch}.iso.

Update 2

Using a shell script, it can be quite easy to collect the pieces for a livecd. I'm not sure what metro can run after steps/capture, but that might be able to do it at some point after.

isolinux and its config are pretty static on an arch, but I would like to see a dynamic way of creating them.

Other than that, just some init (loads of openrc errors) tweaking.

Update 3

I'm using cdupdate.sh to apply a workaround for init/openrc.

Just tweaking left.

LiveUSB

Now, this is slightly easier yet more difficult. A liveUSB image should be the product of:

# dd bs=4096 if=/dev/sda of=funtoo-liveusb.img

However, boot-loaders (EXTLINUX, GRUB) need a real mounted device, which is $DIFFICULTY; especially when considering automating it: metro can (if your portage snapshot is already made) run many instances at the same time without problem; otherwise you'd need a spare partition and fast drives so you can dd off many images (I suspect it would be several hours per image).

Mounting an empty image via loop and writing to it doesn't work AFAIK:

# mount -o loop blank.img /mnt/gentoo

LVM

Some of us are loud proponents for lvm, and installing a gentoo/funtoo instance on an LVM on a USB has the possibility of being *very* practical.

Basically, instead of the squashfs, we have a (compressed or not) lvm image that we mount as our rootfs in the live environment; the "stage 5" (stage 4 + kernel stuff).

To install it, just dd the lvm to the hdd (as long as the hdd has the capacity to hold the lvm image).

This should put a very small partition onto the hdd with the rest zeroed and unused. In the live environment: fdisk in and change the end cylinder of the partition (max it out), then pvresize to get the lvm filling the disk.

Update 1

Unix's "everything is a file" falls down here (just saying).

Update 2

isolinux's documentation mentions isohybrid, which can make the the same livecd also bootable from keys.